Comparison of the diagnostic value of MR imaging and ophthalmoscopy for the staging of retinoblastoma

Diagnostic Imaging for Retinoblastoma Cancer Staging: Guide for Providing Essential Insights for Ophthalmologists and Oncologists

Retinoblastoma is the most common cause of all intraocular pediatric malignancies. It is caused by the loss of RB1 tumor suppressor gene function, although some tumors occur due to MYCN oncogene amplification with normal RB1 genes. Nearly half of all retinoblastomas occur due to a hereditary germline RB1 pathogenic variant, most of which manifest with bilateral tumors. This germline RB1 mutation also predisposes to intracranial midline embryonal tumors. Accurate staging of retinoblastoma is crucial in providing optimal vision-, eye-, and life-saving treatment. The AJCC Cancer Staging Manual has undergone significant changes, resulting in a universally accepted system with a multidisciplinary approach for managing retinoblastoma. The authors discuss the role of MRI and other diagnostic imaging techniques in the pretreatment assessment and staging of retinoblastoma. A thorough overview of the prevailing imaging standards and evidence-based perspectives on the benefits and drawbacks of these techniques is provided. Published under a CC BY 4.0 license. Test Your Knowledge questions for this article are available in the supplemental material.

Orbital Tumors-Clinical, Radiologic and Histopathologic Correlation

Orbital masses include a broad spectrum of benign and malignant entities. Often these masses are asymptomatic or show a slow growth rate, so that emergence of clinical symptoms is prolonged. In this context, cross-sectional imaging plays an elementary role in the characterization of these lesions. Aside from the characterization of the underlying entity, an evaluation of the involved compartments is possible by sufficient imaging, which also facilitates optimal treatment and surgery planning. The purpose of this review is to explore different benign and malignant orbital tumors and their typical appearance in imaging together with histopathologic findings.

MR-EYE: High-Resolution MRI of the Human Eye and Orbit at Ultrahigh Field (7T)

Ultrahigh-field (7T) MRI provides improved contrast and a signal-to-noise gain compared with lower magnetic field strengths. Here, we demonstrate feasibility and optimization of anatomic imaging of the eye and orbit using a dedicated commercial multichannel transmit and receive eye coil. Optimization of participant setup techniques and MRI sequence parameters allowed for improvements in the image resolution and contrast, and the eye and orbit coverage with minimal susceptibility and motion artifacts in a clinically feasible protocol.

Retinoblastoma: What the Neuroradiologist Needs to Know

Retinoblastoma is the most common primary intraocular tumor of childhood. Accurate diagnosis at an early stage is important to maximize patient survival, globe salvage, and visual acuity. Management of retinoblastoma is individualized based on the presenting clinical and imaging features of the tumor, and a multidisciplinary team is required to optimize patient outcomes. The neuroradiologist is a key member of the retinoblastoma care team and should be familiar with characteristic diagnostic and prognostic imaging features of this disease. Furthermore, with the adoption of intra-arterial chemotherapy as a standard of care option for globe salvage therapy in many centers, the interventional neuroradiologist may play an active role in retinoblastoma treatment. In this review, we discuss the clinical presentation of retinoblastoma, ophthalmic imaging modalities, neuroradiology imaging features, and current treatment options.

Diagnostic performance of MRI of post-laminar optic nerve invasion detection in retinoblastoma: A systematic review and meta-analysis

PURPOSE

Preoperative MRI detection of post-laminar optic nerve invasion (PLONI) offers guidance in assessing the probability of total tumor resection, an estimation of the extent of surgery, and screening of candidates for eye-preserving therapies or neoadjuvant chemotherapies in the patients with retinoblastoma (RB). The purpose of this systematic review and meta-analysis was to evaluate the diagnostic performance of MRI for detecting PLONI in patients with RB and to demonstrate the factors that may influence the diagnostic performance.

METHODS

Ovid-MEDLINE and EMBASE databases were searched up to January 11, 2020, for studies identifying the diagnostic performance of MRI for detecting PLONI in patients with RB. The pooled sensitivity and specificity of all studies were calculated followed by meta-regression analysis.

RESULTS

Twelve (1240 patients, 1255 enucleated globes) studies were included. The pooled sensitivity was 61%, and the pooled specificity was 88%. Higgins I² statistic demonstrated moderate heterogeneity in the sensitivity (I² = 72.23%) and specificity (I² = 78.11%). Spearman correlation coefficient indicated the presence of a threshold effect. In the meta-regression, higher magnetic field strength (3 T than 1.5 T), performing fat suppression, and thinner slice thickness (< 3 mm) were factors causing heterogeneity and enhancing diagnostic power across the included studies.

CONCLUSIONS

MR imaging was demonstrated to have acceptable diagnostic performance in detecting PLONI in patients with RB. The variation in the magnetic field strength and protocols was the main factor behind the heterogeneity across the included studies. Therefore, there is room for developing and optimizing the MR protocols for patients with RB.

Evaluation of the role of ultrasound biomicroscopy in advanced retinoblastoma: A prospective study on Asian Indian children

Aim: To evaluate the role of ultrasound biomicroscopy (UBM) in retinoblastoma (RB).Methods: Children with advanced unilateral RB were included. UBM was performed to look for tumour invasion into the anterior segment (AS) and for evaluation of quantitative parameters. Enucleation was done and UBM findings were correlated with histopathology. The main outcome measures were sensitivity and specificity of UBM for detecting AS invasion and comparison of quantitative parameters between the tumour affected and fellow eyes.Results: Fifty patients were evaluated. The mean age was 2.76 ± 1.63 years. Enucleation was performed in 50 eyes. The sensitivity and specificity of UBM for AS invasion were 80% (95% CI, 44-97%) and 95% (95% CI, 83-99%), respectively. UBM showed a sensitivity and specificity of 100% (95% CI, 59-100%) and 95% (95% CI, 84-99%), respectively, for iris invasion, 88% (95% CI, 47-100%) and 100% (95% CI, 92-100%), respectively, for ciliary body invasion, and 63% (95% CI, 24-91%) and 100% (95% CI, 92-100%), respectively, for anterior chamber (AC) angle invasion. Quantitative parameters were studied in 100 eyes. As compared to the fellow eyes, the AC angle was narrow (p < 0.05), posterior chamber was shallow (p = 0.004) and zonular length was increased (p = 0.001) in RB eyes.Conclusion: This clinicopathological study provides valuable insights into the role of UBM for evaluation of anterior extension of RB and for assessment of architectural changes in the AS due to the tumour.

Diagnosis of Postlaminar Optic Nerve Invasion in Retinoblastoma With MRI Features

BACKGROUND

Retinoblastomas (RBs) with postlaminar optic nerve invasion (PLONI) increases the risk of local recurrence or systemic metastasis. Most MRI studies on PLONI focused on optic nerve enhancement and tumor size, with reported relatively high specificity (84-98%) but low sensitivity (37-78%), which shows room for improvement, especially with regard to sensitivity.

PURPOSE

To evaluate the diagnostic performance for detecting PLONI with RB using MRI features.

STUDY TYPE

Retrospective.

POPULATION

Fifty patients with histopathologic PLONI and 70 patients without PLONI of RB.

FIELD STRENGTH/SEQUENCE

1.5T and 3.0T, precontrast axial T₁ -weighted and T₂ -weighted, postcontrast axial, coronal and oblique-sagittal T₁ -weighted.

ASSESSMENT

The eyes were histopathologically analyzed and the preoperative MRI features of the eyes were independently evaluated by three observers.

STATISTICAL TESTS

MRI features suggesting the presence of PLONI were identified by univariate and multivariable analysis. Receiver operating characteristic curve (ROC) and the area under the curve (AUC) were used to analyze diagnostic performance.

RESULTS

Significant independent diagnostic factors for PLONI include: 1: Bilateral tumor (odds ratio [OR], 15.32; 95% confidence interval [CI]: 1.63-143.51); 2: Tumor with total coverage of the optic disk (OR, 6.43; 95% CI: 1.04-39.79); and 3: Optic nerve enhancement (OR, 8.43; 95% CI: 3.50-20.31). On the other hand, isointense signal of tumor on T₂ WI (OR, 0.30; 95% CI: 0.12-0.75) was an independent diagnostic factor in excluding PLONI. ROC analysis showed AUC of 0.84 (95% CI: 0.77-0.91, P < 0.0001) for PLONI. Based on the cutoff of maximum Youden index, the sensitivity, specificity, and accuracy were 82%, 73%, and 77%, respectively.

DATA CONCLUSION

MRI features of RB showed a strong association with PLONI. The model of MRI features demonstrated promising diagnostic performance in detecting PLONI.

LEVEL OF EVIDENCE

4 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:1045-1052.

Magnetic resonance imaging for tumor restaging after chemotherapy in retinoblastoma with optic nerve invasion

PURPOSE

Extraocular retinoblastoma with optic nerve invasion is treated by a multimodal protocol consisting of neoadjuvant chemotherapy, enucleation, and adjuvant therapy. This study was conducted to evaluate the performance of magnetic resonance imaging (MRI) used for tumor restaging in these children after systemic chemotherapy administration.

METHODS

Contrast-enhanced MRI scan of orbits and brain was performed at diagnosis and patients were treated with neoadjuvant chemotherapy. After chemotherapy, MRI scan was repeated for tumor restaging and residual post-laminar thickening and/or enhancement of the affected optic nerve, if any, was recorded. MRI findings were correlated with histopathology in enucleated specimens. The main outcome measures were specificity, sensitivity, and accuracy of MRI in predicting post-laminar invasion after neoadjuvant chemotherapy.

RESULTS

A total of 46 eyes (46 patients) were studied. Optic nerve thickening on MRI had a sensitivity, specificity, and accuracy of 100% (95% Confidence Interval (CI): 64.6-100%), 76.9% (95% CI: 61.7-87.4%), and 80.4% (95% CI: 66.8-89.4%), respectively. Optic nerve enhancement had a sensitivity, specificity, and accuracy of 85.7% (95% CI: 48.7-97.4%), 79.5 % (95% CI: 64.5-89.2%), and 80.4% (95% CI: 66.8-89.4%), respectively. Combined thickening and enhancement of the optic nerve had a sensitivity, specificity, and accuracy of 100% (95% CI: 60.9-100%), 82.4% (95% CI: 66.5-91.7%), and 85% (95% CI: 70.9-92.9%), respectively.

CONCLUSION

MRI is a valuable tool for restaging of retinoblastoma and predicting residual optic nerve disease after neoadjuvant chemotherapy. Combined thickening and enhancement on MRI appeared to be a more reliable indicator of post-laminar invasion as compared to thickening or enhancement alone.

Multiband diffusion-weighted MRI of the eye and orbit free of geometric distortions using a RARE-EPI hybrid

Diffusion-weighted imaging (DWI) provides information on tissue microstructure. Single-shot echo planar imaging (EPI) is the most common technique for DWI applications in the brain, but is prone to geometric distortions and signal voids. Rapid acquisition with relaxation enhancement [RARE, also known as fast spin echo (FSE)] imaging presents a valuable alternative to DWI with high anatomical accuracy. This work proposes a multi-shot diffusion-weighted RARE-EPI hybrid pulse sequence, combining the anatomical integrity of RARE with the imaging speed and radiofrequency (RF) power deposition advantage of EPI. The anatomical integrity of RARE-EPI was demonstrated and quantified by center of gravity analysis for both morphological images and diffusion-weighted acquisitions in phantom and in vivo experiments at 3.0 T and 7.0 T. The results indicate that half of the RARE echoes in the echo train can be replaced by EPI echoes whilst maintaining anatomical accuracy. The reduced RF power deposition of RARE-EPI enabled multiband RF pulses facilitating simultaneous multi-slice imaging. This study shows that diffusion-weighted RARE-EPI has the capability to acquire high fidelity, distortion-free images of the eye and the orbit. It is shown that RARE-EPI maintains the immunity to B₀ inhomogeneities reported for RARE imaging. This benefit can be exploited for the assessment of ocular masses and pathological changes of the eye and the orbit.

Correlation between conventional MR imaging combined with diffusion-weighted imaging and histopathologic findings in eyes primarily enucleated for advanced retinoblastoma: a retrospective study

OBJECTIVES

To determine the diagnostic accuracy of conventional MRI in detecting tumour invasion of advanced intraocular retinoblastoma and to correlate ADC values with high-risk prognostic parameters.

METHOD

The sensitivities, specificities, positive predictive values (PPV), negative predictive values (NPV) and accuracies of MRI in detecting tumour-extent parameters of 63 retinoblastomas were determined. Furthermore, ADC values were correlated with high-risk prognostic parameters.

RESULTS

MRI detected postlaminar optic nerve with a sensitivity of 73.3% (95% CI 44.9-92.2%) and a specificity of 89.6% (77.3-96.5%), while the specificity for choroidal invasion was only 31.8% (13.9-54.9%). Likewise, MRI failed to predicted early optic nerve invasion in terms of low sensitivity and PPV. In contrast, scleral and ciliary body invasion could be correctly excluded with high NPV. ADC values were significantly lower in patients with undifferentiated tumours, large tumour size, as with optic nerve and scleral invasion (all p < 0.05). However, no correlation was found between ADC values and the degree of choroidal or ciliary body infiltration. Additionally, ADC values were negatively correlated with Ki-67 index (r = -0.62, P = 0.002).

CONCLUSIONS

Conventional MRI has some limitations in reliably predicting microscopic infiltration, with the diagnostic efficiency showing room for improvement, whereas ADC values correlated well with certain high-risk prognostic parameters for retinoblastoma.

KEY POINTS

• Conventional MRI failed to predicted microscopic infiltration of the retinoblastoma. • Scleral and ciliary body invasion could be excluded with high NPV. • ADC values correlated well with some high-risk pathological prognostic parameters.

3D turbo field echo with diffusion-sensitized driven-equilibrium preparation technique (DSDE-TFE) versus echo planar imaging in evaluation of diffusivity of retinoblastoma

OBJECTIVE

Compared with echoplanar (EP) diffusion-weighted imaging (DWI), three-dimensional (3D) turbo field echo with diffusion-sensitized driven-equilibrium (DSDE-TFE) preparation DWI obtains images with higher spatial resolution and less susceptibility artefacts. The purpose of this study was to evaluate the feasibility of DSDE-TFE to visualize retinoblastomas compared with EP imaging.

METHODS

This retrospective study was approved by our institutional review boards. Eight patients with retinoblastomas (five males and three females; age range 0-87 months; median 21 months) were studied. For the DSDE-TFE, motion-probing gradients (MPGs) were conducted at one direction with b-values of 0 and 500 s mm^-2 and a voxel size of 1.5 × 1.5 × 1.5 mm³. For the EP imaging, MPGs were conducted at three directions with b-values of 0 and 1000 s mm^-2 and a voxel size of 1.4 × 1.8 × 3 mm³. The apparent diffusion coefficients (ADCs) of each lesion were measured. Statistical analyses were performed with Pearson R and linear correlation coefficients.

RESULTS

Intraocular lesions were clearly visualized on the DSDE-TFE without obvious geometrical distortion, whereas all showed deformity on EP images. On the DSDE-TFE, the ADCs of the lesions ranged from 0.83 × 10^-3 to 2.93 × 10^-3 mm² s^-1 (mean ± standard deviation 1.73 ± 0.73 × 10^-3 mm² s^-1). On the EP images, the ADCs ranged from 0.53 × 10^-3 to 2.03 × 10^-3 mm² s^-1 (0.93 ± 0.53 × 10^-3 mm² s^-1). There was a significant correlation in ADC measurement between the DSDE-TFE and EP imaging (r = 0.81, p < 0.05).

CONCLUSION

With its insensitivity to field inhomogeneity and high spatial resolution, the 3D DSDE-TFE technique enabled us to assess diffusivity in retinoblastomas. Advances in knowledge: DSDE-TFE could enable us to assess the ADC of retinoblastomas without obvious geometrical distortion.

MRI helps depict clinically undetectable risk factors in advanced stage retinoblastomas

This study compared high-resolution MRI with histology in advanced stage retinoblastomas in which ophthalmoscopy and ultrasonography did not give an exhaustive depiction of the tumour and/or its extension. MRI of orbits and head in 28 retinoblastoma patients (28 eyes) treated with primary enucleation were evaluated. Iris neoangiogenesis, infiltrations of optic nerve, choroid, anterior segment and sclera suspected at MR and histology were compared. Abnormal anterior segment enhancement (AASE) was also correlated with histologically proven infiltrations. Brain images were also evaluated. Significant values were obtained for: prelaminar optic nerve (ON) sensitivity (0.88), positive predictive value (PPV) (0.75) and negative predictive value (NPV) (0.71); post-laminar ON sensitivity (0.50), specificity (0.83), PPV (0.50) and NPV (0.83); overall choroid sensitivity (0.82), and massive choroid NPV (0.69); scleral specificity (1), and NPV (1). AASE correlated with iris neoangiogenesis in 14 out of 19 eyes, and showed significant values for: overall ON PPV (0.65), prelaminar ON sensitivity (0.65), and PPV (0.61), post-laminar ON NPV (0.64); overall choroid sensitivity (0.77), PPV (0.59) and NPV (0.73); scleral NPV (0.83); anterior segment sensitivity (1), and NPV (1). Odds ratios (OR) and accuracy were significant in scleral and prelaminar optic nerve infiltration. Brain examination was unremarkable in all cases. High-resolution MRI may add important findings to clinical evaluation of advanced stage retinoblastomas.

Retinoblastoma

Retinoblastoma is the most common neoplasm of the eye in childhood, and represents 3% of all childhood malignancies. Retinoblastoma is a cancer of the very young; two-thirds are diagnosed before 2 years of age and 95% before 5 years. Retinoblastoma presents in 2 distinct clinical forms: (1) a bilateral or multifocal, heritable form (25% of all cases), characterized by the presence of germline mutations of the RB1 gene; and (2) a unilateral or unifocal form (75% of all cases), 90% of which are nonhereditary. The treatment of retinoblastoma is multidisciplinary and is designed primarily to save life and preserve vision.